This was my 2nd or 3rd attempt at building my own engraving cutter. In the past I had tried using various grind geometries with less then stellar results. This was the 1st time I used a pyramid style 3 face grind (on an old carbide endmill shaft) and achieved great results!
The brass cap pictured is only 3/8 diameter with the engravings being cut 0.007" deep. I was so happy with the results I was able to attain with my newly made engraving tool I added the option of custom engravings on all MK1 orders!
Here you can see the 3 sided cutter. To get the best results during the grinding process I placed the carbide blank into my taig lathe headstock. I then attached my rotary tool to the carriage and used the spindle indexing plate to rotate the blank 120 degrees between cuts. I just eyeballed the other angle to look proper and locked the carriage for all cuts. Cuts were taken with a diamond disk which slices carbide remarkable well (even when using my ultra cheap diamond coated disks). From there it went straight into the CNC mill, no further stone work or anything.
Here you can see the engravings after the pen was cleaned and polished. For the size of this cutter and the space on the MK1 endcap 2-3 letters is about the maximum to strike a nice balance between depth of cut and readability.
Thus far I have only cut engravings into soft metals (brass, copper, aluminum, etc) but I would like to try some cuts in steel...while the CNC isn't designed to mill steel I think I could get away engraving it. Best of all is when I nuke the cutting edges I simple chuck it back into the lathe and bring it right back to new.